I've read this page:http://www.modthesims.info/wiki.php...ete_Cache_Files

And many pages about deleting cache, but they don't explicitly say nothing will be lost.

There are lots of things I wonder about getting screwed up when deleting cache.
-plants on the home lot and their states, what has been fed to omni plants etc
-plants in the neighbourhood
-moodlets, wishes, opportunity, any of the progress bars
-outfits, custom palettes for clothes/decor that was saved
-changes to the world or sims like if you alter a neighbour's appearance or career with MC, or delete something on a community lot.
-relationships
-consignment store things not yet sold
-other things I can't think of right now

Can anyone supply a definitive answer about what will or won't be lost? Hopefully it will be found by people like me searching in the future.

I delete my .cache files almost every time I play (due to new mod installations, etc.)
I've never had anything lost. All the above you've mentioned are more to do with save files than the .cache files themselves.
(P.S- Off topic, but GAH, why must my cat always sit in front of the "Post" button when she sits in front of my computer screen? ><)

It's just a cache file of data the game reads for quicker access; it doesn't actually change anything in your game.

However, we're talking about specific cache files as identified in your link. If you start deleting stuff like in your library, or the userpresets file, you will lose stuff. Read the file name twice before deleting so you're not having to resurrect all your custom saved buildings and households from the Recycle Bin you lovingly created because you quickly deleted files without making sure they were the ones you wanted to. One time I ended up selecting the options file by mistake with the 4 cache files. Not a tragedy, but I was sure pissed when the game started at 640X480 resolution, and I had to reset everything myself (too pissed to just restore the file, I made myself set every option over again out of misplaced anger).

I do it all the time and you don't have to worry they reload after you quit the game. It really does help speed up my actions after downloading to many mods to count and never had a problem.

I just tested removing the neighbourhood object & sim package files. I was hoping it would fix my stuck plants problem.

Every mature or harvest plant in the whole town was changed to mature. Lower ages stayed the same.

Didn't fix the plant bug unforch.

Caches are just to speed up your loading times; if you lose anything other than your patience waiting for TS3 to regenerate your 66gigs of custom sideburns, you probably deleted something else you shouldn't have. Try using Delphy's Dashboard to clear caches, I find it easier than clicking around in folders.

As for plant bugs, they hibernate in winter if you have Seasons, and will stay 'stuck' until spring sometime. If you don't have Seasons or it's not winter, you can try using NRaas mods to reset the plants or the lot they're on. DebugEnabler might allow you to set their growth state as well, but I'm not 100% sure on that.

I delete my caches after each game, including the sims3launcherlogfile and the sims3logs. Nothing disappears.

I think it was a false reading when my plants changed to mature because I put the old cache files in and they loaded as mature as well. Like every time I start the game they get reset or something. But that's another thread. I won't worry about deleting caches now, thanks.